City of Patterson
Sewer System Management Plan
2025 Update
Final
May 2025
Table of Contents
Introduction.................................................................................................................................7 Purpose ...................................................................................................................................7 Background..............................................................................................................................7 1 Goals........................................................................................................................................9
1.1 Regulatory Requirements....................................................................................................9
1.2 City Goals...........................................................................................................................9
1.3 SSMP Update Schedule.....................................................................................................10
1.4 Sewer System Asset Overview...........................................................................................10
1.4.1 Location and Service Area...........................................................................................10
1.4.2 Population and Community Served .............................................................................10
1.4.3 Wastewater Collection Systems .................................................................................11
1.4.4 Structures Diverting Storm Water To the Sewer Main....................................................12
1.4.5 Data Management System..........................................................................................12
1.4.6 Service Connections...................................................................................................12
1.4.7 Unique Service Boundary Conditions and Challenge(s)................................................12 2 Organization ...........................................................................................................................12
2.1 Regulatory Requirements..................................................................................................12
2.2 Legally Responsible Official ..............................................................................................13
2.3 Contact Information and Organization Chart ..................................................................13
2.4 Chain of Communication For Reporting SSOs ....................................................................16 3 Legal Authority ........................................................................................................................17
3.1 Regulatory Requirements..................................................................................................17
3.2 Municipal Code ................................................................................................................18 4 Operations and Maintenance Program .....................................................................................20
4.1 Regulatory Requirements..................................................................................................20
4.2 Updated Map of Sanitary Sewer System.............................................................................20
4.3 Preventative Operations and Maintenance Activities ..........................................................21
4.4 Rehabilitation and Replacement Plan ................................................................................22
4.5 Training ............................................................................................................................23
4.6 Equipment and Replacement Part Inventories ...................................................................23 5 Design and Performance Provisions.........................................................................................24
5.1 Regulatory Requirements..................................................................................................24
5.2 Updated design and Construction Standards and Specifications........................................24
5.3 Procedures and Standards ................................................................................................25 6 Spill Emergency Response Plan ...............................................................................................25
6.1 Regulatory Requirements..................................................................................................25
6.2 Notification Procedures ....................................................................................................26 7 Sewer Pipe Blockage Control Program .....................................................................................27
7.1 Regulatory Requirements..................................................................................................27
7.2 FOG Control Plan..............................................................................................................28
7.3 Public Education and Outreach Program ...........................................................................28
7.4 Disposal of Pipe-Blocking Substances...............................................................................29
7.5 Legal Authority to Prohibit Discharges ...............................................................................29
7.6 Grease Removal Devices...................................................................................................30
7.7 Authority to Inspect...........................................................................................................31
7.8 Identification of System Sections Prone to FOG Blockages .................................................33
7.9 Source Control Measures..................................................................................................33 8 System Evaluation and Capacity Assurance Plan and Capital Improvements ............................34
8.1 Regulatory Requirements..................................................................................................34
8.2 System Evaluation and Condition Assessment...................................................................34
8.3 Capacity Assessment and Design Criteria..........................................................................35
8.4 Prioritization of Corrective Action ......................................................................................36
8.5 Capital Improvement Plan.................................................................................................36 9 Monitoring, Measurement, and Program Modifications .............................................................37
9.1 Regulatory Requirements..................................................................................................37
9.2 Information and Record Keeping........................................................................................37
9.3 Monitoring of SSMP Elements:...........................................................................................37
9.4 Assessing Effectiveness of Preventative Operations and Maintenance................................38
9.5 Program Updates..............................................................................................................38
9.6 SSO Trends.......................................................................................................................38 10 Program Audits......................................................................................................................38
10.1 Regulatory Requirements ................................................................................................39
10.2 SSMP Audits Overview.....................................................................................................39
10.3 Audit Schedule ...............................................................................................................39 11 Communication Program.......................................................................................................39
11.1 Regulatory Requirements ................................................................................................39
11.2 Communication with Public ............................................................................................40
Appendices
Appendix A Order No. 2006-0003-DWQ and General Order 2022-0103-DWQ Appendix B SSMP Internal Audit 2022
Appendix C SMMP Internal Audit 2024
Appendix D City’s Existing Wastewater Collection System Map Book Appendix E SSMP Staff Names and Phone Numbers
Appendix F Spill Emergency Response Plan
Appendix G Memorandum of Understanding – WHWD & City of Patterson
Abbreviations
AIPS Advanced Integrated Pond System
BMPs Best Management Practices
Cal-OSHA California Division of Occupational Safety and Health CEUs Continuing Education Units
CIP Capital Improvement Program
City City of Patterson
CIWQS Central Integrated Water Quality System
CMOM Capacity, Management, Operation, and Maintenance
CWEA California Water Environment Association
EPA Environmental Protection Agency
FOG Fats, Oils, and Grease
I/I Inflow and Infiltration
MobileMMS Mobile Maintenance Management System
MOU Memorandum of Understanding
NASTS North Activated Sludge Treatment System
SCADA Supervisory Control and Data Acquisition
SOI Sphere of Influence
SSMP Sewer System Management Plan
SSO Sanitary Sewer Overflow
SWRCB State Water Resources Control Board
WDID Waste Discharge Identification
WHWD Western Hills Water District
WQCF Water Quality Control Facility
WWMP Wastewater Master Plan
Introduction
The Sewer System Management Plan (SSMP) is an update to the City of Patterson’s (City) Sanitary Sewer Management Plan repaired in August 2016 (2016 SSMP). The 2016 SSMP was prepared to satisfy the requirements of California State Water Resources Control Board (SWRCB) Order No. 2006-0003-DWQ, Statewide General Waste Discharge Requirements (WDRs) for Sanitary Sewer Systems. Per the Order, the SSMP must be updated every 5-years to reflect any significant program changes. The WDRs apply to all public entities that own or operate sanitary sewer systems greater than one mile in length that collect and/or convey untreated or partially treated wastewater to a publicly owned treatment facility.
On December 6, 2022, the SWRCB adopted the Order 2022-0103-DWQ, Statewide Waste Discharge Requirements General Order for Sanitary Sewer Systems. This new General Order is effective on June 5, 2023, and supersedes Order No. 2006-0003-DWQ and amendments thereafter.
This SSMP was developed for the City to comply with the requirements in the current Order No. 2006-0003-DWQ and for compliance with Order 2022-0103-DWQ. A copy of Order No. 2006-0003-DWQ and Order 2022-0103-DWQ are provided in Appendix A.
Purpose
The purpose of an SSMP is to:
1. Maintain or improve the condition of the collection system infrastructure in order to provide reliable service into the future;
2. Cost-effectively minimize infiltration/inflow (I/I) and provide adequate sewer capacity to accommodate design storm flows; and
3. Minimize the number and impact of sanitary sewer overflows (SSOs) that occur.
Background
The City operates and maintains its own wastewater collection system and infrastructure withing the City limits. The City’s Public Works Department manages and maintains approximately 63 miles of sanitary sewer lines ranging from 4 to 33 inches in diameter, three lift stations, and the City’s water quality control facility (WQCF). The State’s Waste Discharge Identification (WDID) number for the City’s collection system is 5SS011021.
SSOs are defined as any overflow, spill, release, discharge, or diversion of untreated or partially treated wastewater from a sanitary sewer system. SSOs may cause a public nuisance, particularly when raw untreated wastewater is discharged to areas with high population exposure, and may pollute surface or ground waters, threaten public health,
adversely affect aquatic life, and impair the recreational use and aesthetic enjoyment of surface waters.
An SSMP is required to include the following elements:
1. Goals
2. Organization
3. Legal Authority
4. Operation and Maintenance Program
5. Design and Performance Provisions
6. Spill Emergency Response Plan
7. Sewer Pipe Blockage Control Program
8. System Evaluation and Capacity Assurance and Capital Improvements
9. Monitoring, Measurement, and Program Modifications
10. Internal Audits
11.Communication Program
The titles for the elements match the requirements of Order 2022-0103-DWQ, but also comply with the requirements for the similar elements described in Order 2006-0003- DWQ. Each of these elements is addressed in the following sections including a description of the SWRCB requirement and any supporting information for that element.
The WDRs have established and SSMP implementation schedule based on the size of the agency. The City has a population of approximately 24,790 as of January 1, 2025 and is therefore governed by the schedule established for municipalities greater than 10,000 and less than 100,000.
As part of Order No 2006-0003-DWQ, the SWRCB also established an SSO database that is part of the Central Integrated Water Quality System (CIWQS), a secure, online regulatory and water quality information management system. The SSO database is used to collect and store facility and organizational information as well as monthly SSO or “No SSO” activity details. The City has been reporting all SSOs and “No SSO” reports since first required in 2007.
The City has previously completed a SSMP Internal Audit in 2022 (2022 Audit). The 2022 audit was used as a guide to complete the 2023 SSMP. A copy of the 2022 Audit is provided in Appendix B. The City has most recently completed the SSMP Internal Audit in 2024. The 2023 SSMP was used to complete the SSMP Internal Audit in 2024. A copy of the SSMP Internal Audit 2024 is provided in Appendix C.
1 Goals
1.1 Regulatory Requirements
The goal of the SSMP is to provide a plan and schedule to:
1) Properly manage, operate, and maintain all parts of the City’s sanitary sewer system(s),
2) Reduce and prevent spills, and
3) Contain and mitigate spills that do occur.
1.2 City Goals
Providing quality, safe, and reliable sewer at a reasonable cost is essential to fulfilling the City’s Public Works’ Mission Statement: To “provide the highest level of service to the residents of Patterson while maintaining the community’s infrastructure in the most costeffective manner possible. We constantly strive to improve our customer service and efficiency.” The City has developed the following goals to meet the requirements of the Sanitary Sewer Order and uphold their mission statement:
a) Minimize sanitary sewer overflows.
b) Prevent public health hazards.
c) Minimize inconvenience by responsibly handling interruptions in service. d) Protect the large investment in collection systems by maintaining adequate capacities and extending useful life.
e) Prevent unnecessary damage to public and private property. f) Use funds available for sewer operations in the most efficient manner. g) Convey wastewater to treatment facilities with a minimum of infiltration, inflow and exfiltration.
h) Provide adequate capacity to convey peak flows.
i) Perform all operations in a safe manner to avoid personal injury and property damage.
j) Minimize impacts on environmentally sensitive waterways such as the San Joaquin River.
The City has consistently met the goals. The current maintenance plan encompasses the entire system but also focuses on known hot spots within the system. These are sections of the system that are prone to fats, oils, and grease (FOG). Preventative maintenance minimizes SSOs thereby protecting human health and the environment. Key aspects that have contributed to the City’s current success with state goals are the maintenance and FOG programs. The City has worked to improve these activities, which has resulted in no SSOs in four years. Preventative maintenance is the key to achieving the established goals.
1.3 SSMP Update Schedule
Under Order No. 2006-0003-DWQ, an internal program audit should be conducted at a minimum frequency of once every two years, and the SSMP update must be updated every five years to reflect any significant program changes.
Under the order 2022-0103-DWQ, the City shall update its SSMP every six years after the date of its last Plan Update due date. The City shall conduct an internal program audit at a minimum frequency of once every three years. The schedule for completing the SSMP updates and audits is based on the timelines which started with the adoption of Order No. 2006-0003-DWQ and is not based on the date that the update and audits are completed.
The SWRCB has created the following website for searching the required due dates:
https://www.waterboards.ca.gov/water_issues/programs/sso/lookup/ . The schedule from this website is also provided in Table 1-1.
Table 1-1 – SSMP Updated and Local Audit Schedule
Type Next Due Date
Audit August 2, 2028
SSMP Update August 2, 2031
1.4 Sewer System Asset Overview
The City’s owned assets and service area are described further in this section.
1.4.1 Location and Service Area
The City is located on Highway 33 along the Interstate 5 corridor in the northwestern portion of the San Joaquin Valley, approximately 13 miles southwest of Modesto. The City’s existing Water Quality Control Facility (WQCF) includes flows from the City of Patterson, unincorporated County areas that lie within the City’s sphere of influence (SOI), and the Diablo Grande’s residential and golf course resort community. The City has an agreement with the Western Hills Water District (WHWD) to treat and dispose of Diablo Grande’s wastewater. The WQCF is located at 14901 Poplar Avenue in Stanislaus County approximately three miles northeast of the City’s limits, and adjacent to the San Joaquin River floodplain [1].
The City and WHWD service areas are shown in Figure 1-1.
1.4.2 Population and Community Served
As described in the Background section, the City has a population of approximately 23,781.
The City’s land use designations consist of residential neighborhoods, commercials, industrials, mixed uses, public uses, parks, and open spaces.
1.4.3 Wastewater Collection Systems
The City operates and maintains its own wastewater collection system and infrastructure within the City limits. The City’s Public Works Department manages and maintains approximately 63 miles of gravity sanitary sewer lines ranging from 4 to 33 inches in diameter, three lift stations, and approximately 2500 feet of 12 inch forced main. A map of the City’s existing wastewater collection system is provided in Appendix D.
Figure 1-1 – City and WHWD Service Areas
1.4.4 Structures Diverting Storm Water To the Sewer Main There are no structures diverting storm water to the sewer system.
1.4.5 Data Management System
The City has a Supervisory Control and Data Acquisition (SCADA) control system located in the existing administration building to monitor and control the sewer pump stations. The City also reports SSOs to the SWRCB’s online SSO database.
The City is planning to fully implement sanitary sewer maintenance programs and incorporate plans into the Mobile Maintenance Management System (MobileMMS).
1.4.6 Service Connections
The current service connections for each land use are provided in Table 1-2.
Table 1-2 – Number of Service Connections
Land Use Designation Total Service Connection
Commercial 282
Residential 6862
Total 7,144
1.4.7 Unique Service Boundary Conditions and Challenge(s) The City has no unique service area boundary conditions and challenges. 2 Organization
2.1 Regulatory Requirements
The SSMP must identify organizational staffing responsible and integral for implementing the local SSMP through an organization chart or similar narrative documentation that includes:
• The name of the Legally Responsible Official as required in Section J of Order No. 2006-0003-DWQ and Section 5.1 (Designation of a Legally Responsible Official) of General Order 2022-0103-DWQ;
• The position titles, telephone numbers, and email addresses for management, administrative, and maintenance positions responsible for implementing specific SSMP elements;
• Organizational lines of authority; and
• Chain of communication for reporting spills from receipt of compliant or other information, including the person responsible for reporting spills to the State and
Regional Water Boards and other agencies, as applicable. (For example, county health officer, county environmental health agency, and State Office of Emergency Services.)
2.2 Legally Responsible Official
The City’s Legally Responsible Officials in all wastewater collection system matters are the Deputy Director of Operations and Maintenance and the Deputy Director of Public Works (Deputy Directors). The Deputy Directors are authorized to certify electronic spill reports submitted to the SWRCB, while the Public Works Director is responsible for implementing and maintaining all elements of this SSMP. The names and contact information for the Deputy Directors are included in Appendix E.
2.3 Contact Information and Organization Chart
The organization chart shown in Figure 2-1 indicates the City staff responsible for implementing, managing, and updating the SSMP. A brief description of responsibilities identified with each position follows. The names and phone numbers of staff filing positions are included in Appendix E.
Staff have been identified and trained in the various elements of the SSMP. The number of operators attached to the Collections Division is five in addition to the division’s supervisor.
The five operators have been trained in the aspects of sewer collection system maintenance and SSOs. The operators are sent for additional training as it becomes available through organizations such as the California Water Environment Association (CWEA). All five operators and the division’s supervisor are certified Collection System Operators. In addition, there are other maintenance workers and division supervisors who are trained in collections system maintenance and SSO response procedures. This structure has worked well, and reports are completed in a timely manner.
Figure 2-1 – Organization Chart of City Staff Implementing SSMP City Council
City Manager
Public Works Director
Asst City Manager
Deputy Directors
City Engineer Utility Supervisor
Deputy Director of
Regulatory
Compliance
City Inspector Collections Division Public Works
Inspectors
Collection System
Operators
City Council – Approves and adopts the SSMP, City Standards, and Ordinances.
City Manager – Determines whether various wastes are acceptable for discharging or should be prohibited from discharging into the City collection system; determines when pretreatment, flow control or additional fees will be required; approves plans for construction of monitoring manholes when required; reviews permit applications for compliance with City ordinances, rules and regulations; issues permits; receives notification that work is ready for inspection; regulates quality and quality of industrial waste and monthly sewage charges; collects fees and rental payments; and makes and enforces regulation necessary for safe, economical and efficient management of the City sewer system.
Assistance City Manager – Assists the City Manager with determining whether various wastes are acceptable for discharging or should be prohibited from discharging into the City collection system; determines when pretreatment, flow control or additional fees will be required; approves plans for construction of monitoring manholes when required; reviews permit applications for compliance with City ordinances, rules and regulations; issues permits; receives notification that work is ready for inspection; regulates quality and quality of industrial waste and monthly sewage charges; collects fees and rental payments; and makes and enforces regulation necessary for safe, economical and efficient management of the City sewer system.
Public Works Director – Establishes policy; plans strategy; leads staff; allocates resources; delegates responsibility; authorizes outside contractors to perform services; develops department plans and programs including sewer operations and the Capital Improvement Program; supervises the review of applications for permits for compliance with codes, regulations, and standards; and oversees and coordinates sewer maintenance operations.
Deputy Directors – Deputy Director of Operations and Maintenance and Deputy Director of Public Works are the Deputy Directors. The Deputy Directors assist the Public Works Director in the planning, directing, supervising, and coordinating of department functions and operational activities; assists in the monitoring and preparation of operating and capital improvement budgets and management of personnel assigned to the department; and supervises the operations and maintenance of City infrastructure.
City Engineer – Acts as project manager on public works projects; prepares plans, specifications and preliminary cost estimates; reviews private project development plans for compliance with codes, regulations, and standards; confers with the Public Works Director and maintenance department on sanitary sewer system issues; confers with contractors and consultants on engineering and construction matters; prepares reports on sewer and other public works projects; and coordinates development and implementation of the SSMP.
Utility Supervisor – Plans, organizes, and supervises the maintenance and repair of City wastewater infrastructure; manages field operations and maintenance activities; provides relevant information to agency management; prepares and implements contingency plans; leads emergency response; maintains records of projects assigned and completed; supplies equipment sued and cost incurred; estimates needed equipment and equipment maintenance; investigates and reports SSOs; and trains field crews.
Deputy Director of Regulatory Compliance – Works as needed on applicable permits, laws, and regulations and provides support to all parts of operation. Reviews private project development plans for compliance with codes, regulations and standards.
Civil Inspector – Reviews new and rehabilitated public infrastructure improvements for compliance with codes, regulations, and standards; and provides verbal/written reports to the City Engineer.
Public Works Inspector – Works with City Engineering and contractors on public and private construction projects. Performs SWPPP and other permit inspections.
Maintenance Worker – Works as a member of the field maintenance crew; performs preventative maintenance activities; responds to notifications of stoppages and SSOs; cleans, unplugs and repairs sewer lines; and mobilizes sewer cleaning equipment. The City is working with AFSCME Local 10 to create a Collection System Operator classification to handle collection system maintenance, operation, and repair duties.
2.4 Chain of Communication For Reporting SSOs
The chain of communication for reporting SSOs, from receipt of a complaint or observation to reporting the SSO to the SWRCB, is shown in Figure 2-2. Contact phone numbers for the parties included in the chain of communication are listed in Appendix E along with the names and phone numbers of City staff included in the SSMP Organizational Chart.
To ensure SSOs are reported appropriately, the Public Works staff are trained in SSO reporting procedures and are familiar with the CIWQS web portal. All administrative staff are trained in these procedures as well to have adequate coverage in the event of illnesses or vacation. The SSO reporting process will be described in further detail in the following section entitled “Spill Emergency Response Plan.”
Figure 2-2 – Chain of Communication for Reporting SSOs
3 Legal Authority
3.1 Regulatory Requirements
The SSMP must include copies or an electronic link to the City’s current sewer system use ordinances, services agreements, and/or legally binding procedures to demonstrate the City possesses the necessary legal authority to:
• Prevent illicit discharges into its sanitary sewer system from inflow and infiltration (I/I); unauthorized storm water; chemical dumping; unauthorized debris; roots; fats, oils, and grease; and trash, including rags and other debris that may cause blockages;
• Collaborate with storm sewer agencies to coordinate spill responses, ensure access to storm sewer systems during spill events, and prevent unintentional cross connections of sanitary sewer infrastructure to storm sewer infrastructure; • Require that sewer system components and connections be properly designed and constructed;
• Ensure access for maintenance, inspection, and/or repairs for portions of the service lateral owned or maintained by the City;
• Enforce any violation of its sewer ordinances, service agreements, or other legally binding procedures; and
• Obtain easement accessibility agreements for locations requiring sewer system operations and maintenance, as applicable.
3.2 Municipal Code
The legal authority required for the SSMP by the SWRCB is provided in the City’s municipal code. Title 13 of the municipal code contains three chapters dedicated to the sewer system. The following is a description of these chapters:
13.02 Sanitary Code – Provides rules and regulations for the use and construction of sanitary sewer facilities installed, altered, or repaired by the City.
13.04 Sewer Extension – Provides a process by which owners can request extension of the City’s sewer system through streets or alleys adjacent to their property for the purpose of connecting to the sewer system.
13.08 Outside Sewer Connections – Provides a process, rules, and regulations for governing “any connection with any sewer line of the City, whether within or without the corporation limits of the City, whereby sewage of any type is discharged into such sewer line from any residence, place of business or other location outside of the City corporate limits:” (i.e., satellite systems).
The Patterson Municipal Code for sanitary sewer can be found using the following electronic link: https://www.codepublishing/CA/Patterson13/Patterson13.html .
Portions of these chapters are summarized in Table 3-1 as they pertain to the requirements described above.
Table 3-1 – Legal Authority Checklist
Municipal Code Section Description
Prevention of Illicit Discharges
13.02.490 Prohibits leaders from roofs, surface drains for rainwater or storm sewers, from being connected to
any sanitary sewer and prohibits any surface, storm
water, or artesian well flows from entering the sewer
system
13.02.500 Prohibits the discharge of several specific wastes to any public sanitary sewer
Satellite System Inflow
13.02.510 Lists types of wastes which may be prohibited Proper Design and Construction of Sewers and Connections Permit Requirements
13.02.150 Requires a permit prior to construction of a private sewage disposal system.
13.02.210 Requires a permit prior to construction of a building or lateral sewer intended to connect to any public
sewer
13.02.300 Requires a permit prior to construction, extension, or connection to any public sewer unless the
contractor is under a contract awarded and entered
into by the City
Design Requirements
13.02.170 Requires all private sewer systems to be designed in compliance with the Department of Public Health of
the state and the health department of Stanislaus
County
13.02.230 – 13.02.260 Provides regulations for sewers of adjacent buildings, sewers of old building, cleanouts, and
lifting sewage when sewers are too low to permit
gravity flow
13.02.320 – 13.02.340 Provides regulations for plans, profiles, and specifications required, subdivisions, and
easements or right-of-ways
Construction Requirements
13.02.220 Requires design and construction of buildings and lateral sewers to be in accordance with the
requirements of the City and the City Standard
Specifications.
13.02.310 Requires construction of all sewers within the City to be in accordance with the City Standard
Specifications
13.02.350 and 13.02.360 Provides regulation for persons authorized to perform work and compliance with local regulations
Inspection and Testing
13.02.160 Allows the City to inspect the work at any time for all private sewage disposal systems
13.02.270 Requires the connection of any building or lateral sewers into the public sewer to be made in the
presence of personnel designated by the City
Manager
13.02.290 Requires all buildings and lateral sewers to be tested in accordance with the City Standard Specifications
13.02.370 and 13.02.380 Requires “as-built” drawings and testing of any public sewer to be in full compliance with all
requirements of the Standard Specifications and to
the satisfaction of the City Manager prior to
acceptance by the City
Lateral Maintenance Access
13.02.280 Ensures maintenance access for portions of the service lateral owned or maintained by the City
Limit Discharge of FOG and other Debris
13.02.510 Allows the City to limit the discharge of FOG and other debris that may cause blockages
13.02.540 and 13.02.550 Allows the City to require the installation and maintenance of grease interceptors
13.02.090 Prohibits the depositing of any objectional waste in an unsanitary manner on public or private property
within the City
Enforcement
13.02.880 – 13.02.930 Provides the City authority to issue notices of violations, designate nuisances, provides
disconnection authority, establish reconnection
criteria, and abate nuisances
In November of 2022, City Council approved a Local Limits Study for commercial and industrial dischargers. This will project the Publicly owned treatment works facility and allow continued compliance with the WDR.
4 Operations and Maintenance Program
4.1 Regulatory Requirements
The SSMP must include the items listed below that are appropriate and applicable to the City’s system.
• An up-to-date map of the sanitary sewer system, and procedures for maintaining and providing State and Regional Water Board staff access to the map(s). The maps must show gravity line segments and manholes, pumping facilities, pressure pipes and valves, and applicable storm water conveyance facilities within the sewer system service area boundaries.
• Preventive Operation and Maintenance Activities
• Training
• Equipment Inventory System
4.2 Updated Map of Sanitary Sewer System
The City has a collections system map that displays the location and sizes of all gravity lines, manholes, pumping facilities, and pressure pipes. The maps are presented in grid
format and printed on 11”x17” paper with an index sheet. The City Engineer keeps a master set (electronic and hard copy) of the map, and they are readily available in all Public Works’ offices as well as Collections Division utility trucks. The City has recently incorporated the sewer, storm drain, and water base maps into the City’s GIS System.
As City staff become aware of discrepancies, they mark changes on their maps. The Deputy Directors collect these copies of map sheets with correction and submit them to the Public Works Director who will then provide copies of these corrections to the City Engineer. The affected map grids are corrected, and new pages are printed and distributed accordingly. These updates occur every six months (as needed). The maps are also updated as new developments occur. Once a project has been constructed and final inspection has occurred, the City will request, as one of the punch list items, submittal of record drawings. Once corrections have been received, the City Engineer will provide the revised map sheets within six weeks. Each map sheet has a print/version date in the bottom right-hand corner.
4.3 Preventative Operations and Maintenance Activities
Preventative maintenance work orders are generated by the Public Works Department based on the following maintenance schedule shown in Table 4-1.
Table 4-1 – Maintenance Schedule
Facility Routine Maintenance Frequency
Lift Stations Visual Inspection Daily
Hot Spots Surface inspection of manholes and sewer flows, hydro flushed, cleaning as required, and chemical
treatments as required (i.e., degreasers, odor
control)
Monthly
Sewer Mains Clean with Vactor Truck
CCTV Inspection
Every Eight Years
Sewer Laterals Cleaned and/or chemical treatments Customer Driven The Collections Division is in the process of cleaning the entire sewer collections system.
In addition to a vacuum/mainline cleaning truck, the City has a mainline camera unit to inspect and record the condition of the City’s collection system. From 2018-2022, the Collections crew has cleaned and inspected 11.2 miles of sanitary sewer mains. The crew has also repaired or replaced 24 sanitary sewer laterals. The City has purchased a new vacuum truck and replaced the current (aging) vehicle. The older unit has remained in the in the fleet as a backup to the new truck providing continuous coverage during maintenance/repairs of the new unit. The Water Division has also acquired and has placed in service a vacuum truck that may be used in the event both Collections vehicles are unable to function. The equipment is used to inspect the hot spots in the collection system to determine if the sewer mainline is sound in the areas. The results of the mainline inspections have been positive, and the creation of these hot spots is attributed to FOG.
Public outreach is a component of the City’s FOG program and will be addressed in future activities related to the program.
The City’s system is divided into sectors based on the sewer utility map, and the Collections crew will complete a sector before moving on to the next section. The City uses the MobileMMS asset management software to record the size and condition of pipe, the footage of pipe cleaned, and the type of debris (if any) encountered. The software is installed on an Apple iPad tablet and includes a map of the collections system. The digital map will display the areas that have been serviced once the data is entered. Areas known to have issues with sewer line blockages due to FOG are inspected weekly and chemical treatment such as degreaser or odor control is applied as needed. Residents experiencing issues with their sewer lines call the Public Works Department and City staff are dispatched immediately to address the issue. The incident is then documented in the Department’s work order program (MobileMMS). Calls from residents placed after hours are routed to the City’s answering service and addressed by the City’s on-call personnel.
4.4 Rehabilitation and Replacement Plan
Data obtained during maintenance and inspection activities is evaluated and analyzed based on the following criteria:
1. Line Obstructions
a. Number of prior SSOs due to obstructions at this location b. Cause of obstruction(s)
c. Amount of previous maintenance work performed at this location d. Prior inspection records
e. Overflow quantity and destination
f. Size of tributary area upstream
2. Pipe/Manhole Defects
a. Location
b. Prior inspection records
c. Size, depth, and length of defective line
d. Dept of flow line
3. Replacement
a. Remaining life expectancy
b. Other scheduled construction work at replacement location c. Potential severity of SSO
d. Location and permitting issues
e. Cost
The problem areas are then ranked to prioritize repair, rehabilitation, and/or replacement projects to be included in the CIP (this information is also utilized to prioritize or adjust the routine maintenance schedule).
The City maintains short (1 to 3 years) and long (3+ years) term CIPs which are living documents, updated annually, that help identify current and future City needs. The plans include a schedule and budget for planning, design, construction, and construction administration costs for completing identified projects.
4.5 Training
Operations and maintenance functions are performed by City staff, and training is tantamount to a successful program. The City provides technical skills and monthly safety training programs. Equipment training is obtained from manufacturer representatives and/or vendors of the products/equipment used in the maintenance program. Professional organizations, such as the CWEA, offer training and certification in storm water and waste water collection. The City has staff members certified in these fields who attend seminars and workshops to meet training requirements and obtain continuing education units (CEUs) for recertification purposes.
The City contracts out all confined space operations, therefore no training programs for this type of work are offered currently. Contractors performing any work on the City’s sewer system need to meet or exceed the training requirements of regular staff. The City has a Confined Space Responsibilities checklist outlining items to be provided to the contractor and items to be provided by the contractor including detailed liability contract information.
4.6 Equipment and Replacement Part Inventories
The City has identified critical components of the sewer system and currently maintains an inventory of critical spare parts, including spare parts for vehicles and equipment, which are centrally stored at the Corporation Yard. A 15-year equipment maintenance replacement schedule was implemented in 2008 and will need to be updated by the end of 2023.
The City owns and maintains one emergency generator which is adequate for their sewer system since only three lift stations exist. A standardization policy for the construction of sewer system facilities is in place and is specified in the City’s Standard Specifications.
The City has access to 24-hour emergency pump service, vehicle and equipment service, and parts and materials suppliers. Contact information for these vendors is included in the Emergency Response Plan. The City also maintains a vehicle and equipment list. Separate files are kept on all vehicles and equipment maintenance and parts records.
Additionally, the City owns three vacuum trucks and a mainline camara. The trucks are used to perform maintenance activities as well as address SSOs, and the mainline camera works in conjunction with the vacuum trucks to inspect and record the condition of the facilities in a digital format. In addition to the collections crew, additional staff members are trained in the proper operation of the vacuum trucks.
5 Design and Performance Provisions
5.1 Regulatory Requirements
The SSMP must include the following items as appropriate and applicable to the City’s system:
• Updated design and construction standards and specifications for the construction, installation, repair, and rehabilitation of existing and proposed system infrastructure components, including but not limited to pipelines, pump stations, and other system appurtenances. If existing design criteria and construction standards are deficient to address the necessary component-specific hydraulic capacity as specified in Section 8 (System Evaluation and Capacity Assurance Plan and Capital Improvements), the procedures must include component-specific evaluation of the design criteria.
• Procedures and standards for inspection and testing of newly constructed, newly installed, repaired, and rehabilitated system pipelines, pumps, and other equipment and appurtenances.
5.2 Updated design and Construction Standards and Specifications The City maintains standard specifications for construction of public improvements and inspection and testing of public sewer facilities. The City’s Improvements Standards were approved by City Council on August 17, 2021 (2021 Improvement Standards) [3]. A link to the 2021 Improvement Standards is provided below.
Link: https://www.ci.patterson.ca.us/DocumentCenter/View/6955/City-of-PattersonImprovementStandards?bidId= Details and specifications may be changed to reflect accepted design practices and industry standards. City staff review the standards and make recommendations for updates annually. Recommendations are forwarded to the City Engineer who reviews the proposed updates and makes additional recommendations (if necessary) before inclusion into the standards. Copies of the current Improvement Standards are available through the City’s Public Works Department as well.
Section 8 of the City’s Improvement Standards provides specifications and detailed drawings for the sanitary sewer facilities including:
• Design Flow Rates, Peeking Factors, Pipe Size and Slope • Pipe for Sewer Mains
• Services
• Manholes
• Lift Stations
• Force Mains
• Trench Excavation
• Water in Trench
• Laying and Jointing of Pipe
• Lateral Connections
• Backfill
• Grease Interceptors
• Sewer Main Separation Regulations
• Alignment and Depth of Sewers
• Trench Loading Conditions
• Sewer Laterals
5.3 Procedures and Standards
Section 8 of the City’s Improvement Standards also has specifications for the inspection and testing of new public sewer facilities including:
• Installation
• Cleaning and Flushing
• Television Inspection
• Testing of Sewer Lines
6 Spill Emergency Response Plan
6.1 Regulatory Requirements
The SSMP must include a developed Spill Emergency Response Plan to assure prompt detection and response to spills to reduce spill volumes and collect information for prevention of future spills. The Spill Emergency Response Plan must include procedures to:
• Notify primary responders, appropriate local officials, and appropriate regulatory agencies of a spill in a timely manner;
• Notify other potentially affected entities (for example, health agencies, water suppliers, etc.) of spills that potentially affect public health or reach waters of the State;
• Comply with the notification, monitoring and reporting requirements of this General Order, State law and regulations, and applicable Regional Water board Orders;
• Ensure that appropriate staff and contractors implement the Spill Emergency Response Plan and are appropriately trained;
• Address emergency system operations, traffic control and other necessary response activities;
• Contain a spill and prevent discharge to waters of the State or any draining conveyance system;
• Minimize and remediate public health impacts and adverse impacts on beneficial uses of waters of the State;
• Remove sewage from the drainage conveyance system;
• Clean the spill area and drainage conveyance system in a manner that does not inadvertently impact beneficial uses in the receiving waters; • Implement technologies, practices, equipment, and interagency coordination to expediate spill containment and recovery;
• Implement pre-planned coordination and collaboration with storm drain agencies and other utility agencies/departments prior, during, and after a spill event; • Conduct post-spill assessments of spill response activities; • Document and report spill events as required in the new General Order; and • Annually, review and assess effectiveness of the Spill Response Plan, and update the Plan as needed.
The Spill Emergency Response Plan is provided in Appendix F.
6.2 Notification Procedures
The City’s Emergency Response Plan was updated as part of this 2023 SSMP. The plan is reviewed yearly, and pertinent contact information is updated. The Deputy Directors, each Public Works Supervisor, and on-call staff members have a copy of the plan and a packet of field forms in each respective field vehicle. The packets contain easy to follow flow charts to assist staff members in determining the severity of the spill as well as strategies for dealing with the spill. The City submits a monthly electronic report of all spills or non-spills to the SWRCB.
The Spill Emergency Response Plan includes the following components:
• Notification – During business hours, any reports or complaints of sewer backups or overflows are received through the Public Works Department; work orders are generated, and the Deputy Directors are notified. Maintenance worker(s) are then dispatched to assess, contain, fix, and/or clean-up the problem. After business hours, calls are routed through the answering service who then contact the con-call personnel. The on-call personnel will respond to the call and will notify the Deputy Directors. The City also encourages resident (via website and newsletter) to call Public Works if they are experiencing sewer issues inside the home. The City’s response to such calls is to dispatch a staff member to check the sewer lines that
service the neighborhood in question. This will review if the source of the issue inside the home is due to an obstruction in the City sewer main line or specific to the residence. This practice will help avoid a potential SSO. Staff are instructed to give all calls related to sewer issues/SSOs top priority. • Response – Calls received during business hours will be responded to immediately to minimize the impact of an SSO. The Deputy Directors will dispatch maintenance worker(s) to respond to the call. Calls received after business hours will be responded to within one hour by the Public Works on-call person. Depending on the magnitude of the emergency, additional street maintenance workers may be dispatched as required. Non-emergency calls, even odor complaints, are also investigated immediately and will be responded to within one hour. • Reporting – Once the spill has been contained, the problem has been fixed, and/or the clean-up has been completed, the street maintenance worker or on-call personnel will turn in a completed work order and any other necessary field forms to the Deputy Directors, who is then responsible for reporting all SSOs to the SWRCB and other appropriate agencies, including the CIWQS online database. • Impact Mitigation – There are basically three possible types of failures with the City’s sewer system:
1. Minor line blockage due to grease, debris, etc.
2. Major line blockage due to a broken/collapsed line.
3. Lift station failure.
• Flowcharts to assist personnel in performing an initial evaluation of the overflow/back-up situation, determining the responsible responders (i.e., City, other agency or customer), strategies for clearing blockage and traffic and crowd control, strategies for containing and preventing the discharge of untreated or partially treated wastewater, procedures for sampling, and methods of clean-up. • Training – Staff have been trained in SSO response procedures and safety training meetings are held once a month. Staff continue to learn new techniques from professional organizations through training opportunities. The City has also adopted a training matrix. This is al comprehensive training program for new hires requiring documented training on all equipment they are anticipated to use and training on work tasks they are anticipated to perform. 7 Sewer Pipe Blockage Control Program
7.1 Regulatory Requirements
The SSMP must include procedures to evaluate the City’s service area to determine whether a sewer pipe blockage control program is needed to control fats, oil grease, rags and debris. The procedures must include, at minimum:
• An implementation plan and schedule for a public education and outreach program that promotes proper disposal of pipe-blocking substances;
• A plan and schedule for the disposal of pipe-blocking substances generated within the sanitary sewer system service area. This may include a list of acceptable disposal facilities and/or additional facilities needed to adequately dispose of substances generated within a sanitary sewer system service area;
• The legal authority to prohibit discharges to the system and identify measure to prevent spills and blockages;
• Requirements to install grease removal devices (such as traps or interceptors), design standards for the removal devices, maintenance requirements, best management practices requirements,
recordkeeping and reporting requirements.
• Authority to inspect grease producing facilities, enforcement authorities, and whether the City has sufficient staff to inspect and enforce the fats, oils, and grease ordinance;
• An identification of sanitary sewer system sections subject to fats, oils, and grease blockages and establishment of a cleaning schedule for each section; and
• Implementation of source control measures for all sources of fats, oils, and grease reaching the sanitary sewer system for each section identified above.
7.2 FOG Control Plan
According to the 2022 Audit, the City had four SSOs during the years 2016 and 2018 that were caused by FOG. The City’s staff has prepared and implemented a FOG source control program to reduce the amount of these substances discharged into the sewer system.
7.3 Public Education and Outreach Program
The City currently addresses the public outreach section of the plan by posting information on the City website as well as articles in the citizen newsletter. The articles identify FOG and the proper way for citizens to dispose of such debris. Since 2013, the Public Works Department has embarked on a continuous public outreach campaign featuring many of the programs promoted by the Department. FOG is one of the key programs in the presentations and City staff has taken every opportunity available to reach as many people as possible. With the end of the pandemic, staff are once again able to visit elementary and middle schools via scheduled visits and special occasions such as Public Works Week and Arbor Day celebrations. Public Works operations crews have participated in Career Day events at Yolo Middle School in Newman, CA (Note: they most recently participated in April 2023). Although this is outside of Patterson’s service area, it is indicative of the effort
the City is making in promoting a good FOG program. Public Works continues its public outreach by setting up a booth to promote these programs during the annual Apricot Fiesta and other outdoor events. The Department has been very successful in distributing educational materials at these events and it will continue to participate in the years to come.
The Department has created and instituted an official FOG program that covers all FOG program that covers all FOG producing businesses as well as public outreach. Staff members assigned to the program include a Public Works Deputy Director, Public Works Inspector, and Environmental Compliance Specialist. The number of Public Works Inspectors has increased to three and are now better suited to assist in the program. Staff designed and produced a FOG binder with important outreach material that outlines the program as well as an educational component that describes the hazards of FOG and the equipment necessary to contain the pollutants. Included in the kit are maintenance logs and the procedure for reporting maintenance activities to the City. Also included is the legal authority for requiring the maintenance well as the authority for inspecting grease interceptors facilities. Staff have identified all FOG producing establishments and have conducted meetings with facilities that currently have grease interceptors. City staff continue to conduct the introductory meetings with new businesses as they open in the City. Maintenance activities for the establishment are monitored to ensure that the frequency of the activity is adequate, and that best management practices (BMPs) are being followed.
7.4 Disposal of Pipe-Blocking Substances
For FOG-generating businesses, FOG is collected, transported, and disposed of by a licensed grease hauler in accordance with the California Department of Food and Agriculture.
7.5 Legal Authority to Prohibit Discharges
Section 13.02.510 of the City’s municipal code provides the City the authority to prohibit grease disposal into the City’s sewer system, as follows:
13.02.510 Types of Waste which may be prohibited
No person shall discharge or cause to be discharged the following described substances, materials or wastes if it appears likely in the opinion of the city manager that such wastes may harm either the sewers, sewage treatment process of equipment, or can endanger personnel or property or create a public nuisance. In forming his opinion as to the acceptability of these wastes, the city will give consideration to such factors as the quantities of subject wastes in relation to flows and velocities in the sewers to which they discharge, sewer material, treatment process, treatment plant capacity and other pertinent factors.
7.6 Grease Removal Devices
There are currently older FOG producing establishments that do not have grease interceptors. This is due primarily to a lack of space as these locations are in the downtown district. The Collections Division periodically inspects the sewer mains servicing these facilities in order to determine the volume and impact of the FOG generated by these businesses. Staff recognizes that in some cases, a grease interceptor may not be practical due to the limited space available in some of the older locations and that the cost of an interceptor may cause a financial hardship on some, if not all, of the older businesses that generate FOG. Staff will consider alternatives (such as a grease trap in lieu of an interceptor) or on a case-by-case basis.
Sections 13.02.540 and 13.02.550 of the City’s municipal code require grease interceptors be provided and maintained as follows:
13.02.540 Interceptors required.
Any type of business or establishment where grease or other objectionable materials may be discharged into a public or private sewage main or disposal system shall be required to provide a grease, oil and sand interceptor when in the opinion of the city one is necessary for the proper handling of liquid wastes, containing grease in excessive amounts, or any flammable wastes, sand and other harmful ingredients. Grease interceptors, including grease traps, are grease removal devices that interrupt the flow of wastewater, allowing grease and solids to separate out before the wastewater enters the public sewer system. Interceptors shall conform to the following:
A. The size of grease interceptors shall be determined as described in the Uniform Plumbing Code and as approved by the city.
B. Interceptors shall be so installed and connected that they shall be at all times easily accessible for inspection, sample collection, cleaning and removal of grease and other ingredients.
C. Waste discharge from fixtures and equipment in establishments which may contain grease or other objectionable materials including, but not limited to, scullery sinks, pot and pan sinks, dishwashers, food waste disposals, soup kettlers, and floor drains located in areas where such objectionable materials may exist may be drained into the sanitary waste through the interceptor when approved by the city; provided, however, that toilets, urinals, wash basins, and other fixtures containing fecal material shall not flow through the interceptor.
D. Discharges entering interceptors shall not exceed one hundred ten degrees Fahrenheit.
E. Abandoned interceptors shall be emptied and filled as required for abandoned septic tanks. (Ord. 739 (part), 2013: Ord. 250 § 706, 1974).
13.02.550 Maintenance of Interceptors.
All grease, oil and sand interceptors shall be maintained by the owner, at his expense, in a
continuously efficient operation at all times.
All grease, oil and sand interceptors shall be maintained by periodic removal of the accumulated grease. The use of chemicals to dissolve grease is specifically prohibited. No accumulated grease shall be introduced into any drainage piping or public or private sewer.
The discharger shall develop and maintain a record of periodic maintenance and pumping of the grease interceptor. Records shall be retained for a period of not less than three years. A copy of the cleaning record shall be maintained at the facility and made available to the city upon request.
Pumping should be sufficiently frequent to prevent objectionable odors, surcharge of the removal device causing pass-through or interference with the operation of the sanitary sewer system.
When a grease interceptor is cleaned, the removed sediment, liquid and floating material shall be legally disposed of in a manner other than to city’s collection system.
All interceptor owners shall always provide immediate access to the interceptor chambers for the purpose of inspection, sampling, cleaning and maintenance. At no time shall any material, debris, obstacles or other obstructions be placed, which will prevent immediate access to the interceptor.
Regular inspection of grease interceptors will be conducted by the city, the frequency of which will be determined by the public works director. (Ord. 739 (part), 2013: Ord. 250 § 707, 1974).
7.7 Authority to Inspect
Section 13.02.960 of the City’s municipal code provides the authority for an unauthorized representative of the City to inspect grease producing facilities as follows:
13.02.960 Powers and authorities of inspectors.
Any duly authorized employee of the city shall carry evidence establishing his position as an authorized representative of the city and upon exhibiting the proper credentials and identification shall be permitted to enter in and upon any and all buildings, industrial facilities and properties for the purposes of inspection, reinspection, observation, measurement, sampling, testing and otherwise performing such duties as may be necessary in the enforcement of the provisions of
the ordinances, rules and regulations of the city. All persons shall be held strictly responsible for any and all acts of agents or employees done under this chapter.
Upon being notified by the city manager of any defect arising therefrom in any sewer or of any violation of this chapter, the person or persons having charge of the work shall immediately correct the same. (Ord. 250 § 1201, 1974).
Sections 13.02.880 through 13.02.930 of the City’s municipal code provides authority to issue notices of violations, designate nuisances, provide disconnection authority, establish reconnection criteria, and abate nuisances as follows:
13.02.880 Authority of City generally—Notices of violations.
The charges and rentals levied pursuant to the ordinance codified in this chapter shall be collected by the city manager, who shall make and enforce such regulations as may be necessary for safe, economical and efficient management and protection of the city sewage system, the city sewage treatment and disposal works, and such regulations as may be necessary for the regulation, collection, rebating and refunding of such charges or rentals.
In the event of a violation of any of the laws of the state, the ordinances of the city or rules and regulations so established referring to the discharge of sewage, the city shall notify the person or persons causing, allowing or committing such violation, in writing, specifying the violation and requiring or implementing any or all of the following actions as determined by the city.
A. Require the user to submit, for approval, a detailed time schedule of specific actions the user shall take in order to correct or prevent said violation.
B. Require user to cease or prevent further violation within five days after the receipt of such notice.
C. Immediately disconnect sewer service.
D. When discharge of wastewater causes an obstruction, damage, or other impairment to public sewerage facilities, the city manager may assess a charge against the user for work required to clean or repair the facilities and add such charge to the user’s monthly charges for use of public sewerage facilities.
E. Violation of the provisions of this chapter may result in fines levied at twentyfive dollars for the first offense, fifty dollars for the second offense and one hundred dollars for the third and subsequent violations.
F. Any person violating any of the provisions of this chapter shall be liable to the city for any expense, loss or damage occasioned the city by reason of such violation. (Ord. 739 (part), 2013: Ord. 250 § 1101, 1974).
13.02.890 Nuisances designated.
Continued habitation of any building or continued operation of any industrial facility in violation of the provisions of the ordinance codified in this chapter or any other
ordinance, rule or regulation of the city is a public nuisance. The city may cause proceedings to be brought for the abatement of the occupancy of the building or industrial facility during the period of such violation. (Ord. 250 § 1102, 7974).
13.02.900 Disconnection authority.
As an alternative method of enforcing the provisions of the ordinance codified in this chapter or any other ordinance, rule or regulation of the city, the city shall have the power to disconnect the user or subdivision sewer system from the sewer mains of the city. (Ord. 250 § 1103, 1974).
13.02.910 Reconnection.
When service has been disconnected as provided in this chapter, the city may require that the person or persons requesting that service be reestablished furnish a surety bond in the sum of five hundred dollars payable to the city and conditioned upon compliance with the provisions of this chapter before granting permission to make such reestablishment of service and any other terms imposed by the city. (Ord. 250 § 1104, 1974).
13.02.920 Nuisance abatement
During the period of such disconnection, habitation of such premises by human beings constitutes a public nuisance; whereupon the city shall cause proceedings to be brought for the abatement of the occupancy of the premises by human beings during the period of such disconnection. In such event, and as a condition of reconnection, there is to be paid to the city a reasonable attorney’s fee and cost of suit arising in the action. (Ord. 250 § 1105, 1974).
13.02.930 Article provisions as means of enforcement only.
The city declares that the foregoing procedures are established as a means of enforcement of the terms and conditions of its ordinances, rules and regulations, and not as a penalty. (Ord. 250 § 1106, 1974).
7.8 Identification of System Sections Prone to FOG Blockages Over the past several years, the City has identified specific section, or hot spots, of the sewer system that are subject to blockages caused by FOG. Typically, these are identified because of complaints, or SSOs, and the resulting investigation. As an area is identified, it is added to the schedule for routine cleaning and maintenance, as discussed in Chapter 4.
This has proven to be an effective method for reducing blockages and preventing SSOs resulting in FOG. The City will continue to address any new hot spots in the same manner.
7.9 Source Control Measures
The City provides educational information for customers to control FOG at the source. As described previously, the City regularly distributes public outreach materials. The City also regularly meets with FOG producing establishments. The City targets the following schedule for inspections of establishments with grease removal devices:
Table 7-1 – Inspection Schedule for Grease Removal Devices
Grease Removal Device Frequency of Inspection
1,200 gallons or larger Quarterly
Less than 1,200 gallons Quarterly
Removal Devices Located in Kitchen Quarterly
8 System Evaluation and Capacity Assurance Plan and Capital Improvements
8.1 Regulatory Requirements
The SSMP must include procedures and activities for:
• Routine evaluation and assessment of system conditions; • Capacity assessment and design criteria;
• Identification of risk and prioritization of corrective actions; and • A capital improvement plan.
More detailed requirements for each of these procedures and activities listed above are included in each section below.
8.2 System Evaluation and Condition Assessment
The SSMP must include procedures to:
• Evaluate the sanitary sewer system assets utilizing the best practices and technologies available;
• Identify and justify the amount (percentage) of its system for its condition to be assessed each year;
• Prioritize the condition assessment of system areas that:
o Hold a high level of environmental consequences if vulnerable to collapse, failure, blockage, capacity issues, or other system deficiencies; o Are located in or within the vicinity of surface waters, steep terrain, high groundwater elevations, and environmentally sensitive areas; o Are within the vicinity of a receiving water with a bacterial-related impairment on the most current Clean Water Act section 303(d) List; • Assess the system conditions using visual observations, video surveillance and/or other comparable system inspection methods;
• Utilize observations/evidence of system conditions that may contribute to exiting of sewage from the system which can reasonably be expected to discharge into a water of the State;
• Maintain documents and recordkeeping of system evaluation and condition assessment inspections and activities; and
• Identify system assets vulnerable to direct and indirect impacts of climate change, including but not limited to: sea level rise; flooding and/or erosion due to increased storm volumes, frequency, and/or intensity; wildfires; and increased power disruptions.
As described in Section 4.3, the City has a mainline camera unit which is used to inspect and record the condition of the City’s collection system. The City’s maintenance schedule goal is to CCTV inspect the sewer mains on a ten-year cycle. Locations that hold a high level of environmental consequences, are in challenging terrain, or are near surface waters, including irrigation laterals, are given higher priority for inspection. Records are maintained using the MobileMMS asset management software. Because the City is not located near the ocean or areas susceptible to wildfires, the City’s assets are less vulnerable to direct and indirect Impacts of climate change. However, assets located in areas prone to flooding should be assigned a higher priority.
8.3 Capacity Assessment and Design Criteria
The Plan must include procedures to identify system components that are experiencing or contributing to spills caused by hydraulic deficiency and/or limited capacity, including procedures to identify the appropriate hydraulic capacity of key system elements for:
• Dry-weather peak flow conditions that cause or contribute to spill events; • The appropriate design storm(s) or wet weather events that causes or contributes to spill events;
• The capacity of key system components; and
• Identify the major sources that contribute to the peak flow associated with sewer spills.
The capacity assessment must consider:
• Data from existing system condition assessments, system inspections, system audits, spill history, and other available information; • Capacity of flood-prone systems subject to increased infiltration and inflow, under normal local and regional storm conditions;
• Capacity of systems subject to increased infiltration and inflow due to larger and/or higher intensity storm events as a result of climate change; • Increases of erosive forces in canyons and streams near underground and aboveground system components due to larger and/or higher-intensity storm events; • Capacity of major system elements to accommodate dry weather peak flow conditions, and updated design storm and wet weather events; and • Necessary redundancy in pumping and storage capacities.
According to historical records, the City has not experienced any SSOs caused by deficiencies in capacity. The City adopted a Wastewater Master Plan in April 2016 (2016 WWMP) which included a capacity evaluation. The results of the capacity evaluation confirmed that the sewer system has sufficient capacity for peak flow events. The City has a process of requesting updates of the hydraulic model, first developed in the 2016 WWMP, to project impacts from potential developments prior to City approval to ensure that the collection system and treatment plant have sufficient capacity.
8.4 Prioritization of Corrective Action
Chapter 8 of the 2016 WWMP included Capital Improvement Program (CIP) projects for the wastewater collection system and the treatment plant to continue providing sanitary sewer service to current and future customers. The CIP projects in the 2016 WWMP were prioritized based on near-term improvements or buildout improvements. The near-term improvements were based on the findings of a capacity evaluation and condition assessment.
8.5 Capital Improvement Plan
The CIP is required to include the following items:
• Project schedules including completion dates for all portions of the capital improvement program;
• Internal and external project funding sources for each project; and • Joint coordination between operation and maintenance staff, and engineering staff/consultants during planning, design, and construction of capital improvement projects; and Interagency coordination with other impacted utility agencies.
The sewer CIP listed in the City’s annual budget for Fiscal Year 2022-2025 is summarized in Table 8-1.
Table 8-1 – Sewer CIP Projects for Fiscal Year 2025-2028 Description Expenditures
WQCF Expansion Phase III $33,300,000
Ward Avenue Sewer Lift Station $937,000
Total $34,237,000
The annual budget includes more detailed information regarding funding sources for these projects. All projects are coordinated with the City’s operation and maintenance staff, engineering staff, and consultants from planning through to construction and any applicable impacted utility agencies. The City annually updates the CIP based on input from City staff and completed studies.
9 Monitoring, Measurement, and Program Modifications
9.1 Regulatory Requirements
The SSMP must include an adaptive management section that addresses Plan implementation effectiveness and the steps for necessary Plan improvement, including:
• Maintaining relevant information, including audit findings, to establish and prioritize appropriate SSMP activities;
• Monitoring implementation and measuring the effectiveness of each SSMP Element;
• Assessing the success of preventative operation and maintenance activities; • Updating SSMP procedures and activities based on results of monitoring and performance evaluations; and
• Identifying and illustrating spill trends, including spill frequency, locations, and estimated volumes.
9.2 Information and Record Keeping
The City currently monitors and maintains records for the following items:
• Number, cause, and locations of blockages.
• Number, cause, location and volume of SSOs.
• Number and reason for customer complaints.
• Response time.
• Date, length of pipe and cleaned, and debris found.
The following items are also monitored and/or measured to determine the effectiveness of the SSMP, assess the effectiveness of the maintenance program, and update program elements as appropriate:
• Number and location of blockages due to FOG.
• Number and location of SSOs due to FOG.
• Number and location of FOG producing facilities.
• Total number and volume of SSOs.
• Number of repeat SSOs.
• Number of mainline blockages.
9.3 Monitoring of SSMP Elements:
The monitoring activities for each SSMP element are described in each section.
9.4 Assessing Effectiveness of Preventative Operations and Maintenance The current maintenance activities performed on the collections system and the FOG program have helped to been effective as demonstrated by having no SSOs for the past five years. Effectiveness of system operations and maintenance should be evaluated by receiving input from staff, reviewing records, and historical SSOs.
9.5 Program Updates
The SSMP is required to be updated to maintain current information and adjust the specific programs as necessary to meet the goals stated in Section 1. The Deputy Directors are responsible for reviewing the above-listed information at least annually to assess the effectiveness of the various elements of the SSMP. Significant information, such as contact numbers, names, chain of communication, etc. will be updated as required. The annual assessments or audits will be utilized to determine whether additionalchanges need to be made to the SSMP. In accordance with the General Order 2022-0103-DWQ, the SSMP will be thoroughly reviewed and updated every six years, considering program audits and annual reports for the data monitored and measured.
9.6 SSO Trends
Historical SSOs will be reviewed to assist the City with determining if adjustments to the operation and maintenance program and CIP are necessary. The SSO trends from 2016 to 2022 are shown in Figure 9-1.
Figure 9-1 – SSO Chart
10 Program Audits
0 0.5
1 1.5
2 2.5
2014 2016 2018 2020 2022 2024 2026
Number of SSO
Year
10.1 Regulatory Requirements
The SSMP shall include internal audit procedures, appropriate to the size and performance of the system, for the City to comply with Order No. 2006-0003-DWQ and Order 2022-0103- DWQ.
10.2 SSMP Audits Overview
The last SSMP audit was completed in 2024 as described in Chapter 1. According to Order No. 2006-0003-DWQ, at a minimum, the audits should be prepared every two years and a report must be kept on file.
In 2022, the SWRCB issued a public notice and release the Order 2022-0103-DWQ to update, expand and clarify the requirements in Order No. 2006-0003-DWQ. Order 2022- 0103-DWQ requires an internal program audit at a minimum frequency of once every three years, based on the timeless first started with the adoption of Order No 2006-003-DWQ.
At a minimum, the audit must:
• Evaluate the implementation and effectiveness of the City’s SSMP in preventing spills;
• Evaluate the City’s compliance with the General Order; • Identify SSMP deficiencies in addressing ongoing spills and discharges to waters of the State; and
• Identify necessary modifications to the SSMP to correct deficiencies.
The City shall submit a complete audit report that includes:
• Audit findings and recommend corrective actions; and
• A proposed scheduled for the Enrollee to address the identified deficiencies.
10.3 Audit Schedule
The City recently completed an internal program audit in 2024. The next audit is due on August 2, 2028 as shown in Table 1-1.
11 Communication Program
11.1 Regulatory Requirements
The SSMP must include procedures for the City to communicate with:
• The Public for:
o Spills and discharges resulting in closures of public areas, or that enter a source of drinking water, and
o The development, implementation, and update of its Plan, including opportunities for public input to Plan implementation and updates. • Owners/operators of systems that connect into the City’s system, including satellite systems, for:
o System operation, maintenance, and capital improvement-related activities.
11.2 Communication with Public
The City maintains a web site (http://www.pattersonca.gov) to inform the public of City activities. General and other important information is available to the public. Tips on acceptable use of garbage disposals and contact information for reporting sewer issues are provided. Other communication tools include utility bill inserts and articles in the City’s Citizen Newsletter. As previously stated, the Public Works Department has made public outreach a priority and takes every opportunity to present educational materials year-round.
Communication with Stakeholders
Additional communications with stakeholders, i.e., developers, restaurant owners, and users with the potential for large discharges, are provided through the City’s Standard Specifications, general correspondence, and inspections.
Communication with Satellite Systems
The WHWD is responsible for providing water and sewer service to Diablo Grande subdivision. Wastewater from Diablo Grande is discharged into the City’s sewer system and is the only satellite system served by the City. WHWD is responsible for preparing an SSMP for their system. City staff and Diablo Grade personnel meet as needed. The Memorandum of Understanding (MOU) agreement between the City and WHWD is attached as Appendix G.
References
1. California Regional Water Quality Control Board Central Valley Region Order R5- 2018-0070 Waste Discharge Requirements for the City of Patterson Water Quality Control Facility.
2. City of Patterson Wastewater Master Plan, prepared by Black Water Consulting Engineers and NV5, April 2016.
3. City of Patterson Improvement Standards, prepared by the City of Patterson, approved by City Council on August 17, 2021.
Appendix A
Order No. 2006-0003-DWQ
wqo2006_0003
General Order 2022-0103-DWQ
Certified Sanitary Sewer Systems General Order
Appendix B
SSMP Internal Audit 2022
Available upon Request.
Appendix C
SSMP Internal Audit 2024
Available upon Request
Appendix D
City’s Existing Wastewater Collection System Map Book
Available to view upon request.
Appendix E
SSMP Staff Names and Phone Numbers
Staff Name Title Phone Number
Fernando Ulloa City Manager 209-895-8015
Michael Willett Director of Public Works
Assistant City Manager
209-895-8065
Tiffany Rodriguez Director of Engineering 209-895-8075
Xavier Guluarte Deputy Director 209-895-8166
Will Barrera Deputy Director 209-895-8162
Dave Gonsalves Collections Supervisor 209-895-8165
Appendix F
Spill Emergency Response Plan
The Spill Emergency Response Plan is available upon request.
Appendix G
Memorandum of Understanding between WHWD and the City of Patterson Available upon request